The present invention is with respect to tubular rotors for regenerative heat exchangers for the transfer of heat in two flows of material making their way through the rotor of the heat exchanger in parts thereof that are walled off from each other. The rotor is made of a heat vehicle material, that is heated up by the first, hotter flow and is cooled down by the second, cooler flow or current. The separate zones of the rotor in which heating up and cooling down take place are walled off from each other and the rotor is turned in the housing of the heat exchanger so that the heat vehicle material is put firstly in contact with the hotter and then with the cooler flow in turn. The rotors that have so far been used in the prior art have the form of a tubular roller, through which two currents of material make their way, preferably in counter-current, in a direction normal to the lengthways axis of the roller. The direction of motion of the currents is first inwards and then outwards through the outer wall of the rotor so that the motion of the materials is in fact generally radial. The inside of the rotor is shut off into separate spaces in a way in keeping with the desired purpose of stopping mixing of the currents with each other. The fact that each of the currents is moved a second time through the wall of the rotor is responsible for a specially high efficiency of the heat exchange and because the motion is in counter current continuous heating is effected; in fact a heat exchanger designed on these lines may be run very effectively, as for example for recovery of heat from stale air from dwellings or working premises. However other designs of heat exchanger have been used, in which rotors, that is to say almost any form of structure that is regularly turned, are used for the transfer of heat. To this end the currents may be moved through a turning hollow body in an axial or axial-radial direction.
For the design of rotors, and more specially of tubular heat exchanger rotors in the form of rollers, a wide selection of different materials has been put forward. A homogeneous form of the wall of the rotor is for example possible if ceramics or porous synthetic resins such as open pored foam resin are used. Furthermore heat exchanger rollers have been designed using a more or less dense wire compact. In a further suggestion made in the past, such rotors were to be made in the form of composite bodies, such rotors being made up for example of sheet metal rings or of a number strips of sheet metal running along parallel to the axis of turning and placed about the rotor.
The shortcoming of such known systems is that the efficiency of the heat transfer is only low and/or the resistance to the flow is overly great. In the case of homogeneously structured rotors there is furthermore some trouble in connection with the fact that the heat vehicle material lets through the flow not only in its desired direction but furthermore in all other possible directions. If for example such a rotor is used in a heat exchanger in which the flows are moved in counter current two times in a radial direction through the exchanger, whatever steps are taken there will still be a flow, even within the heat vehicle material, in the round-the-axis direction of the rotor. This being the case, the two flows will then be mixed, a highly undesired event. In theory rotors in the form of composite bodies are better at keeping the flows separate. However known designs do however have the shortcoming that because of their complex form they may only be manufactured at a high price. For example heat exchanger rollers have in the past been been made by riveting or welding together separate metal disks into assemblies; furthermore other designs have been made using small metal plates that were placed together in the form of large vessels, as for example in the form of baskets with wire coiled round them or with coiled wire forming the wall thereof, such baskets then together forming the wall of the rotor. However the manufacture of any of these designs is so heavy on labor that they may not be put into industrial production. This being the case, rotors in the form of composite or compound bodies have so not come into general use to any marked degree.